Partial source discrimination in near field acoustic holography

Decomposition techniques based on principal component analysis (PCA) and pa rtial coherent output power (PCOP) analysis are applied to scanning near fi eld acoustic holography (NAH) in order to identify partial sources. Where l ocation of partial sources is uncertain, inaccessible, or the underlying ph ysical process is not well understood, reference transducers may produce ou tputs which are not independent. It is shown that intercorrelated reference s can restrict the decomposition process using PCA. Under these circumstanc es PCOP analysis provides a valuable additional tool for an understanding o f the physical model. (C) 1998 Elsevier Science Ltd. All rights reserved.